Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017
Income Taxes [Line Items]
Excess tax benefit, amount	$ 3,500
Tax Cuts And Jobs Act Of 2017, change in tax rate, deferred tax asset, provisional income tax expense (benefit)	12,900
Valuation allowance, additional	28,100
Accrued interest or penalties related to uncertain tax positions	10
Total amount of unrecognized tax benefits	97
Canada | Research and development
Income Taxes [Line Items]
Tax credit carryforwards	$ 1,700
Tax credit carryforward expiration year	2037
Domestic tax authority
Income Taxes [Line Items]
Net operating loss carryforwards	$ 51,400
Net operating losses expiration beginning period	2019
Federal net operating losses expiration ending Period	2037
Tax credit carryforwards	$ 10,000
Federal credit carryforward expiration, beginning period	2018
Federal credit carryforward expiration ending Period	2037
State and local jurisdiction
Income Taxes [Line Items]
Net operating loss carryforwards	$ 53,200
Net operating losses expiration beginning period	2028
Tax credit carryforwards	$ 2,100
Foreign tax authority | Ireland
Income Taxes [Line Items]
Net operating loss carryforwards	$ 3,200
Accounting Standards Update 2016-16 | Accumulated Deficit
Income Taxes [Line Items]
Cumulative effect of new accounting principle in period of adoption		$ (7,000)